Boat hulls may include a collar assembly located in the outward uppermost portion of the boat hull. This flotation may be filled with air, foam, or combination thereof. The location of this buoyant material provides increased stability particularly in the advent water intrusion or a swamped state. Hence, it is ideal to achieve level floatation in these adverse conditions.
In general, the air and/or the foam are sealed in the collar assembly. For instance, the collar assembly may be comprised of a collar structure that defines a closed volume in which the air or the foam is disposed. Traditional rigid tubular collar assemblies have several drawbacks. For instance, these types of air-filled assemblies maintain a closed volume. In the advent of a puncture or water intrusion, the closed volume will increase in displacement and therefore suffer from a decrease in stability and performance. To offset these negative characteristics rigid tubular collar assemblies may implement chambers or expanding foam to mitigate water intrusion. The chambers add additional weight and manufacturing challenges and only partially mitigate the problem of increased displacement and decreased stability and performance. The expansion foam is sprayed or injected into the closed volume(s) and expands to fill or substantially fill the closed volume.
However, when the expansion foam is exposed to water, the expansion foam may absorb at least a portion of the water. Absorption of the water increases the weight of the collar assemblies and negatively affects the buoyancy, performance, and stability of the boat hull. Once the expanding foam absorbs water, it must be replaced.
Similarly, tubular non-rigid collar assemblies, such as utilized on Rigid-Hull Inflatable Boats (RHIBS), have several drawbacks. The non-rigid tubular collar assemblies rely on an outer protective membrane to provide a closed volume. The closed volume may be air-filled or filled with non-expanding foam. The outer protective membrane is prone to puncture, which may result in the loss of the buoyant properties, decreased performance, etc. Furthermore, the outer protective membrane is also prone to environmental (such as ultraviolet) damage and must be periodically replaced at significant cost. Lastly, the non-rigid tubular collar assemblies have no structural properties. Accordingly, the non-rigid tubular collar assemblies are often subject to damage, and increase hull resistance, with dynamic loading and maneuvering operations.
The subject matter claimed herein is not limited to embodiments that solve any disadvantages or that operate only in environments such as those described above. Rather, this background is only provided to illustrate one example technology area where some embodiments described herein may be practiced.